"Our brains are so terrifically oversized, we have to keep inventing things to want, to buy," Vonnegut said with a shudder. "If you think of the 8 million people of greater New York charging out of their houses every day in order to monitor the planet, it is a terrifyingly destructive force.

'Stupidity May Save Us'

"Among other things," he said of this giant computer lodged between humanity's collective ears, "it is capable of creating the Third Reich of Germany, which in fact so demoralized the world that I don't think we'll ever recover."

His big-brain theory is at the heart of "Galapagos" (Delacorte Press), his 11th novel: Big brains have gotten civilization in so much trouble that its remnants have ended up on one of the barren islands off Ecuador where Darwin concocted his theories of evolution. Of course by this time, a million years in the future, mankind's descendants not only have vastly smaller brains, but also flippers, beaks and, in some cases, soft, seal-like fur.

An Alarming Idea

The idea was so alarming in certain quarters that when an excerpt of "Galapagos" was to appear in Esquire a few months ago, an agitated young fact checker called Vonnegut at home, insisting that there were no records of de-evolution.

"Sure there are," Vonnegut said. "For one thing, the penguins presumably gave up on flying at some point or another."

Inverse evolution was, after all, an idea that popped into Vonnegut's own brain four years ago after a cruise he took to the Galapagos with his wife, photographer-author Jill Krementz.

But after he got home, back to his big, airy town house in the Manhattan literary enclave known as Turtle Bay, Vonnegut got to thinking: "Suppose human beings were shipwrecked on those islands? What would happen? Because all those animals out there have no business being there, you know. So I was thinking, how would human beings adapt?

"Of course there were no things to make tools out of out there. Just twigs, maybe some lava for hand axes. We would have to become very different sorts of animals."

Now many scientists might view Vonnegut's thinking as unconventional. Even Kurt Vonnegut would readily concede his logic sometimes transcends the ordinary.

Said Vonnegut: "My brother is in the same business. He's nine years older than I am. He's a research scientist. We look at things in an unusual way."

A physicist, Vonnegut's brother "has had a great deal of success in turning things upside down and looking at them in unusual ways." For example, while so many of his physicist colleagues were busy smashing atoms and such, "my brother got very, very interested in weather. He did some research and he realized nobody knew much about it."

Specialize in Science

At Cornell University, Kurt Vonnegut had started out intending to specialize in natural sciences. But soon after signing on as a biochemistry major, he realized he had "no gift for it whatsoever."

Still, the scientist's curiosity persisted. As Vonnegut became more focused on the chemistry of the cranium, "Everybody else was hoping we would develop an extra lobe on the brain so we would get smarter and cure cancers and end wars and all. But I was willing to entertain the notion that maybe that wasn't the way it worked, that the bigger our brains get, the more catastrophic it becomes."

Talking about the vast computer, the great big mass of neurons humans carry atop their shoulders, Vonnegut is struck by a further irony. "We are extravagantly alert," he observed, "and frequently wind up in hospitals because our computers are so overheated." But in fact, "what we want to do, so many of us, is go lie on a beach. That is what people want to do, to swim in a blue lagoon."

And so, to Vonnegut, a future, a million years from now, of a de-evolutionized society on a tiny Pacific island didn't sound so bad at all.

"Because look at what the future actually is, now. It's old people's homes. It's bag ladies. Wouldn't it be nicer if everybody, absolutely everybody, could look forward to lying on a beach?

"Our cousins, the seals and sea lions are so happy. They are so content."

Luckily for mega-brained mankind, Vonnegut said, "It is a very forgiving planet. Grotesque mistakes of evolution are forgiven."

For instance, "I mean, what is so great about a giraffe? Or the elephant? It's much too big."